Category: marine and aquatic life

Readers’ wildlife photos

August 9, 2026 • 8:15 am

Glory be—a few regulars have sent in some lovely wildlife photos, so I can post some critters today. These intertidal critters come from UC Davis math professor Abby Thompson, who does great marine photography on the California coast. Abby’s captions are indented, and you can enlarge her photos by clicking on them.

These are probably the last of the summer tidepool photos.  The (spectacular!) final nudibranch is one that I’ve only found once up here before- it’s usually a slightly more southerly species.  If the El Niño comes through as predicted, we should see more this coming year.

The first four animals are chitons, the roly-poly’s of the ocean.     They have a common structure- 8 shell plates, surrounded by a mantle.   The structure of the mantle and the sculpturing on the shell plates, (sometimes) allows identification to species.     The Mopalia (this seems to be a made-up word) chitons have some kind of hairs or feathery things on the mantle.  The type/quantity/form of the hairs can be distinctive.    The first three creatures are in this genus.

Mopalia lionata:

Mopalia lionata: close-up of the feathers on the mantle:

Mopalia spectabilis (tentative ID):

Mopalia spectabilis: close-up of the stripes/hairs on the mantle:

Genus Mopalia – I can’t tell the genus, but liked the photo:

The Lepidozona chitons have small overlapping scales on the mantle and beautiful sculpturing of the shell plates:

Lepidozona cooperi:

Lepidozona cooperi- close-up of the mantle:

Lepidozona cooperi- close-up of the sculpturing:

Diodora aspera (Rough keyhole limpet):

Genus Paranamertes (ribbon worm): There’s a specific local species called a “purple ribbon worm”, and one might think this one would qualify, but it turns out (thanks inaturalist experts!) that identifying to species is tricky in this genus:

Finishing up with some nudibranchs. . .

Corambe steinbergae – chomping on its favorite bryozoan prey, on which it is virtually invisible:

Diaphoreolis lagunae – Laguna Beach aeolid:

And the gorgeous:

Certat0d0ris rosacea: Hopkin’s Rose. Wouldn’t you love to know the sequence of adaptations that led to this?:

Stripes on the beach, early in the morning. It looked as though someone had ruled paths for the water to flow down the beach:

Sunset over Tomales Point:

Readers’ wildlife photos and videos

July 17, 2026 • 8:15 am

Today we have photos and videos of the California intertidal taken by math professor Abby Thompson of UC Davis. Her captions and IDs are indented, and you can enlarge the photos by clicking on them.

Just a few more great low tides for the summer. By August the kelp is so lush, it becomes harder to find interesting creatures, so I’m enjoying June and July.  These photos were taken during the full moon at the end of June.

Amblyosyllis anae (marine worm- it seems to be a summer of worms). This genus is relatively rare (or at least hard to find) here.   I had picked up a piece of sponge to look at under a microscope, and this guy crawled out, so I was lucky.  It was about ¼” long, and lively, as you can see in the video which follows.

Amblyosyllis anae video:

Megalorchestia corniculata (beach flea)- part of the beach clean-up crew.

Dirona picta (nudibranch):

Genus Eudendrium (hydroid):

Class Hydrozoa; this is the medusa (baby jellyfish) form of a hydroid, possibly of the Eudendrium in the previous picture (they were in the same dish). I don’t know what the yellow blob it’s attached to is; in the video following you can see it trying to detach itself:

Hydrozoa video:

Family Phoronidae– yet another type of marine worm, a “horseshoe worm”:

Genus Haliclona (sponge) – it takes an expert and/or a microscope to determine species for sponges. This type is very widespread, and a great color:

Ancula pacifica (tiny nudibranch):

Dendraster excentricus (Sand dollar) This is the “test” (internal skeleton) of a kind of flattened sea urchin. The live urchins stay below the low tide line, and they live in big clusters, sometimes propped up perpendicular to the sand.      Sort-of like the drawing of the oysters in Lewis Carroll’s “The Walrus and the Carpenter”, but underwater, and without the little shoes.

Mussel tracks- not tracks, of course, but for some reason mussels release droplets (presumably seawater?) when they’re exposed at low tide:

Anthopleura artemisia (moonglow anemone):

Moonset over Tomales Point. Moonset on June 30 was just before sunrise, making for some cool lighting:

Readers’ wildlife photos

June 21, 2026 • 8:15 am

Today’s collection is from math prof Abby Thompson at UC Davis, who sends us intertidal photos from California. Abby’s IDs and captions are indented, and you can enlarge her photos by clicking on them.

The photos were taken at Dillon Beach.

Orienthella piunca (nudibranch), with eggs (the white squiggly things), and a small crab spectating”:

Crab tracks- these always look to me like some complicated bicycle tire track, but apparently it’s just what happens if you skitter sideways on your claws. The crab is buried in the sand at the end of the trail, close-up in the next photo:

Crab- probably Romaleon antennarium, Pacific rock crab. Hunkering down, waiting for the tide to come back in:

Epiactis handi (sea anemone).  This is the unusual species of Epiactis which seems to occur only in a single (and hard-to-access) location near me.   I like to check in on them periodically:

Aegires albopunctatus (nudibranch) Salt-and-pepper nudibranch:

Pycnogonum stearnsi (Sea spider). Nestled into the seaweed, completely out of the water, on top of a rock:

Emerita analoga (Pacific sand crabs). Walking the beach at low tide sometimes it looks as though the sand is puckered- that’s likely to be bevy of some kind of tiny sand crab.     This photo shows the “puckering” from a distance of a few feet:

Pacific sand crabs from close up. A footstep will spook them, and they bury themselves completely in a split second.  Not a great photo, but if you look carefully I think you can see each one has its stalked eyes poking up:

Mopalia muscosa (mossy chiton). The inside of the shell- the animal is long gone, leaving these beautiful interior colors:

The beach at sunrise.

Readers’ wildlife photos

June 9, 2026 • 8:15 am

I forgot to post part 2 of Abby Thompson‘s latest batch of California intertidal photos, so here they are (the first batch is here). Abby’s captions and IDs are indented, and, as always, you can enlarge the photos by clicking on them.

The stars of this set, improbably enough, are two flatworms.   The first two pictures are of the elegant Eurylepta californica, which I think of as the “art-deco flatworm”.  It’s rare up here; I’ve found it once before.  The next flatworm (Family Euryleptidae) is an undescribed species.   It’s been recorded several times, almost all in the Monterey Bay area.    This is its third sighting (as recorded on inaturalist) this far north.  There isn’t agreement on the genus. It’s a beauty, and it’s unusual to have such a striking animal remain undescribed.   Both worms are about ¾” long.

Eurylepta californica (striped polyclad flatworm) Art deco flatworm:

Eurylepta californica:

Family Euryleptidae (Yellow frilly flatworm):

The starfish plague of several years ago was devastating along the coast, and several species (like the incredible sunflower stars) have not recovered, but the ochre stars are back with a vengeance.     I see many more of them than of the bat stars, but the next picture is one of each buddying up on a rock above the low tide line.

Patiria miniate and Pisaster ochraceus (bat star (red) and ochre star (yes, purple)):

The next three pictures are a slightly deceptive series.    I’m not sure that the first two pictures really are otter tracks, but the alternative is probably raccoon tracks, and otter is a better match.   They did not, in fact, end on the beach right next to the where I saw the otter in the third picture.   But at least the third picture below is definitely an otter.   This almost surely is a river otter, not a sea otter, as are most seen around here.

Otter tracks:

Close-up of otter tracks:

Lontra canadensis (North American river otter):

Finally, the roof of a cave, with sea anemones (green and pink– Anthopleura xanthogrammica and Anthopleura elegantissima) and sponges (the bright red-orange, not possible to ID from a photo):

Readers’ wildlife photos

June 1, 2026 • 8:15 am

Today we have pictures from the shore of New Jersey taken by Jan Malik.  Jan’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

Here are a few pictures from my walks on Cape May and Sandy Hook, taken this April.

Starting from the Atlantic Ocean (eastern) shore on Cape May, I met this pair of American Oystercatchers (Haematopus palliatus). In Cape May, a section of the beach is fenced off to protect nesting sites for them and for Piping plovers. They are feisty birds and every spring there is a competition for nesting sites; the bird on the right is calling at another Oystercatcher:

The pair took off to drive out the intruder:

The place where I found that pair was littered with the remains of Sand fleas (possibly Emerita talpoida). These fossorial crustaceans normally stay buried in the sand, exiting only when the sand is awash with the shallow tide, but Oystercatchers’ bills are well adapted to dig them out. I think the birds ate only the soft and juicy parts of their telsons, leaving the crustaceans mortally wounded and unable to move:

These Sand fleas are small and difficult to catch alive. That’s what their front end and first pair of legs look like. These crabs dig backwards, starting from their telson, and the front pair of legs is used as a sand anchor:

Another arthropod – the Horseshoe crab (Limulus polyphemus), came ashore, atypically for it, on the Atlantic Ocean side of the peninsula. These are treacherous waters for these spiderlike creatures, for they are easily flipped over by ocean waves and become stranded. They are an interesting part of the Delaware Bay ecosystem and I may share more pictures of them later:

On the Delaware Bay shore of Cape May, there were already many Laughing gulls (Leucophaeus atricilla), which mostly move south in winter but return to their breeding grounds in the spring. They are quite similar to the Eurasian Black-headed gull:

Terns also made their appearance. I think this may be a Forster’s tern (Sterna forsteri) because of the lack of black tips on its primaries and its pure white underbelly, but they are difficult to tell apart from Common terns (Sterna hirundo):

The terns landed on old quay pilings and started courting. There’s no way to tell females from males other than by their courting behavior; males can be slightly larger, but the difference is less than 5%, which is hardly discernible to the human eye:

The courting consists of the two mates trying to look “smug”, with wings drooped, necks extended, and bills pointed toward the sky:

Then there’s the courtship dance and ritual feeding. Here is a fragment of it, taken from a large distance, so I’ve compensated for the lack of pixels by cobbling together this composite. The male presents a fry to the female and then, if she accepts (which is not a given), circles around the female while stomping his feet:

On my way home, I stopped at Sandy Hook, a sand spit where shore gun batteries protecting New York Harbor were once located. It is now a prime nesting site for Ospreys (Pandion haliaetus):

The former Army garrison required many houses for the officers, and these are now excellent nesting sites for Ospreys. Standing in the center of Officers Row (as the area is called), I counted four nests on top of chimneys:

The meadow below the houses was full of American robins (Turdus migratorius) fattening up for the nesting season by preying on earthworms. I know little about annelids, but I’m going to go out on a limb and say it is the common earthworm (Lumbricus terrestris), since it is a favorite prey for robins:

Finally, moving to the class Mammalia, here are Sandy Hook’s harbor seals (Phoca vitulina), congregating on rocks exposed by low tide (the tide was rising so, one by one, the seals were forced to slip back into the water). There are eight seals in this picture, but I counted 15 in total. Their population around the New York inlet has increased in recent years, which may soon put them on a collision course with the fishing industry:

Readers’ wildlife photos

May 27, 2026 • 8:15 am

Today we have some intertidal photos taken in California by UC Davis math professor Abby Thompson. Abby’s captions and IDs are indented, and you can enlarge her photos by clicking on them.

May is a great month on the California coast, with extreme high and low tides.   Here are some photos from the most recent, excellent, set:

Pollicipes polymerus (Gooseneck barnacles). I’ve shown these, and some relatives, several times before, but they’re amazing animals. In case you think it’s too many barnacles, Darwin spent eight years looking at barnacles.   “Originally planning a brief month-long study to establish his credentials in invertebrate zoology, he became deeply immersed and cataloged every known living and fossil species.”  (Google AI).  I’m not sure what the green is doing here, presumably just growing on top of the animals.   Some relatives of the nudibranchs stay green from what they eat, and retain bits with the ability to photosynthesize, most famously the adorable leaf sheep:.

Dendronotus venustus (nudibranch):

Paciocinebrina lurida (a snail):

Tonicella lokii (flame-lined chiton):

Genus Tegula (maybe) (another snail). There was a hermit crab living in the shell- I didn’t get a good photo of him.    I’m not sure the genus is correct, but the shell was so pretty I wanted to post it:

Nucella ostrina (Northern striped dogwinkle). About the common name—well, it has stripes.   And it’s a “winkle” (a word you have to love), or “little whelk”.  The dog part, I dunno.   They’re very common, and voracious. Some species of Nucella (not sure about this one) can be used to make a deep purple dye, which used to be hard to come by.  There’s a fun account of making the dye here, although I’m afraid many snails must have been sacrificed in the process:

Paradialychone ecaudata (worm):

Limpet, probably Lottia pelta (shield limpet). The little lacy edge is tentacles: “Pallial tentacles are tiny, sensory structures lining the mantle margin (pallium) of limpets. . . The tips and shafts of these tentacles are covered in dense tufts of non-motile cilia, which act as sensory receptors.” (Google AI):

Seagulls at sunset:

As always, thanks to experts on inaturalist for help with some IDs.   Camera is an Olympus TG-7.

Readers’ wildlife photos

May 12, 2026 • 8:15 am

Reader Ephraim Heller has sent some lovely photos of humpback whales, including their recently-discovered and amazing behavior of bubble-netting.  His captions and IDs are indented, and you can enlarge the photos by clicking on them.

Pacific herring (Clupea pallasii) spend most of the year dispersed across the open North Pacific, but each spring they converge on Sitka Sound to spawn. The 2026 spawning biomass was estimated at roughly 233,000 tons of mature herring. This attracts commercial fishermen, fishing birds, Steller sea lions, gray whales, humpback whales (Megaptera novaeangliae), and… me.

Here’s a humpback whale jumping for joy:

And here is Sitka Sound, with Mount Edgecumbe (a dormant volcano) in the background:

The scientific name of humpback whales is Megaptera novaeangliae, meaning “big-winged of New England,” due to their oversized pectoral flippers and first observations off of New England. These flippers increase their agility and enable their unique behavior: bubble-net feeding. Here are views of the baleen:

Bubble-net feeding is not a fixed behavioral pattern; it is a culturally transmitted skill, and not every humpback population practices it. The behavior has been documented extensively in Southeast Alaska, and a long-term study published in January 2026 in Proceedings of the Royal Society B tracked its spread in the Kitimat Fjord System of northern British Columbia over a 20-year period (2004–2023). Of 526 individually identified whales, roughly half were observed bubble-net feeding at least once, with more than 92% of those events occurring in a group context:

The behavior gained momentum after the 2014-2016 marine heat wave (“the blob”) that reduced prey availability across the northeastern Pacific. Researchers interpret this as whales adopting a more efficient foraging strategy in response to environmental stress, and transmitting that knowledge through their social networks:

The hunt begins when a group of humpbacks locates a school of small prey — herring, krill, or juvenile salmon. One whale, often referred to as the “bubble-blower,” dives beneath the school and begins exhaling air through its blowhole while swimming in a tightening upward spiral. The released air rises as a cylindrical curtain of bubbles. Fish do not readily cross this curtain, so as the spiral contracts, the school is compressed into an increasingly dense ball:

Meanwhile, one or more other whales in the group produce “food call” vocalizations: loud, frequency-modulated cries that vibrate the swim bladders of herring, causing them to clump even more tightly together. The calls also appear to serve a coordinating function among the whales themselves, signaling when to begin the final ascent. I could occasionally hear the food calls on the deck of my observation boat:

When the prey is sufficiently concentrated, the group orients below the net and lunges upward in near-unison, mouths agape, through the center of the bubble column. At the surface, each whale engulfs thousands of fish in a single pass, then strains the water out through its baleen plates as it rolls and closes its jaws. Groups involved in a single feeding event can range from two to around 16 individuals (according to the literature), each surfacing in roughly the same position relative to the others on every lunge. It’s hard to tell exactly how many bubble-netters are in this photo, but I think it is more than 16:

Quantitative work using drone footage and bio-logging tags has found that solitary humpbacks actively adjust the number of bubble rings, net diameter, and the spacing between individual bubbles from one dive to the next. This level of fine-tuning (“manufacturing” a tool and modifying it based on conditions) contributed to a 2024 study’s argument that bubble nets qualify as tools under standard definitions. On average, a well-constructed net can increase the prey density available in a single lunge by roughly sevenfold, without measurably increasing the whale’s energetic expenditure:

No other baleen whale species does this, and biomechanics research suggests morphology is the reason. A 2025 study comparing turning performance across seven mysticete species found that bubble-net feeding humpbacks achieved centripetal accelerations that exceeded the upper limits recorded in comparable maneuvers by all six other species tested. The humpback’s large pectoral flippers generate substantial lift, which helps the animal bank inward tightly and decrease its turning radius enough to close a spiral into a true net. Other whale species, even if they could theoretically attempt the maneuver, would likely burn too much energy to make the strategy worthwhile:

My next post will include photos of other animals that come to Sitka sound to enjoy the herring feast.